Automatic telephone system.



D. S. HULFISH.

. AUTOMATIC TELEPHONE SYSTEM.

I APPLICATION FILED MAR. 29. 19M- RENEWED DEC. 23, I914.

1,147,864. Patented July 27, 1915.

2 SHEETSSHEET 1.

Z/FTNEwES INVENTOR,

COLUMBIA PLANGGRAPH 60.. WASHINGTON. u. c.

D. S. HULFISH.

AUTOMATIC TELEPHONE SYSTEM.

APPLICATION FILED +1.29. 1911. RENEWED 05c. 23.1914.

1,147,864. Patented July 27, 1915.

2 SHEETS-SHEET 2.

FIQ4. 7

Z/IITNESSES INVENTQR,

COLUMBIA PLANOGRAPH CO.,\VI\SXHNGTON, u. C

UNITED STATES PATENT OFFICE.

DAVID S. HULFISI-I, OF TORONTO, ONTARIO, CANADA,ASSIGNORTO CANADIAN INDE PENDENT TELEPHONE COMPANY, LIMITED, OF TORONTO, CANADA, CORPORATION OF CANADA.

AUTOMATIC TELEPHONE SYSTEM.

Specification of Letters Patent.

Patented July 2'7, 1915.

Application filed March 29, 1911, Serial No. 617,702. Renewed December 23, 1914. Serial No. 878,825.

To all whom it may concern:

Be it known that I, DAVID S. HULrisH, a citizen of the United States of America, and a resident of Toronto, county of York, Province of Ontario, and Dominion of Canada, have invented a new and useful Improvement in Automatic Telephone Systems, of which the following is a specification.

My invention pertains to automatic selecting systems in which a movable electric terminal is required to search among the units of a group of units and to detect and con nect with a unit in that group which is temporarily electrically differentiated from the other units of the group.

In a telephone system of automatic or semiautomatic type, devices are used in which a moving element searches among the members of a group of fixed elements and selects and connects temporarily With the first idle element found, rejecting elements which bear a lousy test or guard condition. It is to such devices as this that my invention specifically pertains. I

VJhen a moving member, as for instance a brush carried by a rotating shaft, is the searching electrical element, the momentum of the moving parts must be overcome to stop the brush when a contact piece representing an idle trunk or outline is engaged. The angle of travel of the moving elements after the idle contact is engaged, is substantially lost motion in the operation of the apparatus, yet a reasonable amount of this lost motion must be provided for, since no physical object can be stopped instantaneously. This angle must be occupied by the individual contact detected that the search ing brush may not overshoot the detected contact and this in turn limits the number of such contacts which may be searched among by the moving brush. As the speed of the moving part increases the angle of each element searched over must be increased and the number in the circle reduced, since the angle required to stop the moving part will become greater by reason of the increased speed. Thus a balance must be attained involving (a) the speed of the moving brush, the movement of the parts attached thereto and (c) the angle subtended by each element searched over or the number of such elements in a circumference. It is to an improved solution of this prob- 1cm that my invention is directed.

I provide a multiple searching brush moving over a plurality of fixed contact plates, the circuits and mechanisms associated with the brush being such that the angle required for stopping the brush may be greater than the angle subtended by one of the fixed contact plates. In other words, I provide a mechanism which, having detected a fined contact plate upon which a stop should be made, permits its detector brush to overshoot the detected plate, yet stops upon the detected plate with its operating brushes properly associated therewith and Without disturbing the circuits or electric conditions of contact plates adjacent to the one detected. I accomplish this by providing a multiple searching brush in which a leading brush member first detects the sought condition, the further operating circuits of the device being completed by a set of brushes displaced angularly to follow the leading or primary detecting brush in such manner that the operating brushes engage the detected segment and perform the required functions independently of the detecting brush, thus permitting the detecting brush to overshoot and leave the detected plate. I provide further that the detecting brush is deprived of its functions, while a detected and seized plate is held by the operating brushes, thereby avoiding interference with the next following plate of the series of fixed plates with which perhaps the detecting brush would engage because of its overshooting. By this arrangement of parts, my device permits the use of a narrower angle for the fixed plates; or on the other hand, it permits a higher permissible speed in the rotating parts, thus providing a more eflicient detecting device.

In the drawings which accompany this specification and in which like parts are designated by like numerals throughout, Figure 1 shows central oflice mechanism and circuits for one form ofapparatus embodying my invention; Figs. 2, 3 and i jointly show a sub-station adapted to operate in connection with the central ofiice of Fig. 1; Figs. 5 and 6 show modifications of Fig. 1.

The three sub-station figures show the same sub-station in three conditions of opera-tion, Fig. 3 showing the sub-station in a condition of rest or idleness with the receiver hung upon the hook, Fig. 4 showing the sub-station in the condition of attempting to call the central otlice, the receiver hav ing been removed from the hook and the hook having been permitted to move up ward through a portion of its travel, and Fig. 2 showing the same substation in c0ndition of conversation, the hook having completed its upward travel.

The system illustrated by these figures is that of a call-detecting system for a telephone exchange. Three lines are represented connecting with the jacks 47, 48, 49 respectively and provided with cut-0E relays 44, 45 and 46 respectively. Signal lamps 47, 48, 49 are associated with the jacks. Relay 30 acts as line relay for the three lines and for as many additional lines as may be represented by fixed contact plates accessible to the brushes 16 and 16.

Shaft 14 is rotated constantly in the direction of the arrows and as indicated by the arrows upon the belt 22, upon pulley 22. The power from the pulley 22 to the shaft 14 is transmitted through the friction clutch 21. Shaft 14 carries block 15, which carries brush 15 and shaft 14 carries also block 16, which carries the multiple brush comprising the pair of brushes 16 and 16. Shaft 14 also carries two electrical contact rings 17, 1S, engaging fixed brushes 17 18 and shaft 14 carries also relay 30 and magnet 29 with its armature 25 and associated switching springs. Ratchet 23 is a fixed ratchet at tached to a part 24 of the frame of the mechanism. Armature 25 carries dog 25. It will be seen that when the magnet 29, carried by the shaft 14, attracts its armature 25 and'revolves the armature upon its pivot, 25 the dog 25 will engage a tooth of the fixed ratchet 23 and impede the movement of the shaft 14, so that the friction clutch 21 will permit the shaft 14 to stop, while the pulley 22 continues to rotate. This stoppage will continue so long as the dog 25 engages the ratchet 23, or in other words, so long as magnet 29 remains charged.

The operation by which a telephone station, as the one illustrated in Figs. 2, 3 and 4, is enabled to cause its signal lamp, as 47, to glow, is as follows :Upon lifting the receiver from the hook, the station passes from the condition of Fig. 3 to that of Fig. 4, in which earth at 7 is connected through elements 6, 3, S and 2, to line wire 13 (Figs. 4 and 1) conductor 60, left armature of relay 44 and contact plate 60. In the course of the revolution of the shaft 14, brush 16 will engage fixed plate 60 and the circuit from earth will be extended through 60, 16 35, 28, 26, 39, 30, 40, 36, 17, 17 and battery 19 to earth at 20, energizing relay 30. By closing its contact pair 32, the relay 30 will energize magnet 29 over the circuit 19, 17 17, 3e, 29, as, 32, 37, 1s, 18. Magnet 29 will attract its armature 25 and force dog 25 into a notch of ratchet 23, which is identified with contact plate 60 jack 47 and lamp 47. As a result, the moving parts are brought to a stop with brush 16 in contact with plate 60 and brush 15 in contact with plate 62, brush 16 being permitted to pass beyond plate 60. By the attraction of armature 25, resulting in stopping the shaft 14, switch springs 26, 27 28 have been operated so that spring 28 is isolated, thus isolating brush 16 and the springs 26, 27 are connected, so that the circuit energizing relay 30, and initially completed through 60, 16 35, 28, 26, 39, is changed and relay 30 is held charged through a circuit comprising in part elements 60, 16, 34, 27, 26, 39. This circuit is maintained as long as relay 44 is uncharged and during the continuance of this condition a circuit exists which is closed through contact pair 31 of relay 30 as follows: 20, 19, 17, 17, 36, 31, 33, 15, 62, right armature of 44, 62, 47 and earth. This illuminates lamp 47 and a manual operator in charge of that lamp will respond by inserting the plug 90. By the insertion of the plug 90 the current flows through battery 19, body of plug 90, body of ack 47 to conductor 61, helix of 44 and earth, charging relay 44, breaking its contacts, extinguishing lamp 47 and discharging relay 30, which breaks its contacts and discharges magnet 29, which releases dog 25 from fixed ratchet 23 and permits shaft 14 to revolve again under power received through friction clutch 21. To complete the operation of the sub station which at this time is in the condition illustrated in Fig. 4, the manual operator by means of her key 91, closes a circuit through elements 19, 92, 91, a tip of plug 90, short spring of jack 47, line wire 12 (Figs. 1 and 4) helix of magnet 11, switch elements 4, 5, 3, 6 to earth 7, charging magnet 11; its armature 10 is attracted,.releasing interference member 9, which permits the apparatus to assume the condition shown in Fig. 2 in which the only circuits at the sub-station are the ringing and talking bridges. Jack 48 and line 48 with the associated line conductors 48, 42, 43, are served by fixed contacts 72, in connection with the same brushes 15, 16, 16 relay 30, etc., as described in connection with jack 47. Brushes 16 and 15 form an operating set of brushes with which set brush 16 is associated as a leading or auxiliary detector brush.

A desirable modification of the system of Fig. 1., is shown in Fig. 5, in which con ductors 34 and 39 are united and in which switch element 27 is omitted. In this modification the electrical function of the armature 25 is to remove from brush 16 its connection with the relay 30, so that the brush 16 does not in any way afi'ect the circuits connected with the next fixed contact plate in order, with which it may make contact in its overshot position while shaft 14 is at rest and while brush 16 is giving desired service to the detected contact plate and its associated equipment.

Fig. 6 shows a modification of Fig. 1 in which the switch springs 26, E27, 28 of the clutch armature 25 are replaced by the contact pair 94 of the relay 95. In this modification, the brush 16 is isolated as soon as the companion brush 16 engages the fixed plate 60. The preliminary energization of the relay 30 is effected over the circuit 7 c, s, s, 2, 13, 60, 00, 16 35, 9-1 39, 30, 40, 86, 17, 17, 19, 20 and subsequent energization is etlected over the circuit 7, 6, 3, 8, 2, 13, 60, 60, 16, 34, 95, 39, 80, a0, 36, 17, 17', 19, 20.

t is obvious that modifications, other than those shown, may be made, and it is obvious further that my invention is in? dependent of the nature of the switching equipment which I have illustrated at &7, 428, ll) and 90, and that the switching equipment there represented may be either manual or automatic in nature. Such modifications do not depart from the spirit nor narroa the scope of my invention.

Iaving thus described my invention, what I claim as new and desire to secure by United States Letters Patent is:

1. In an automatic telephone exchange; a series of fixed elements; a pair of brushes movable over said elements; a circuit comprising in part a path from a starting point to one of said brushes and in part a path from the same starting point to one of said elements; a source of current in said circuit; and means contained in said circuit for interrupting said circuit immediately after its closing.

2. In an automatic telephone system, a series of fixed contact plates; a pair of brushes, movable over said plates; a source of electric current; a circuit comprising in part a path from one ofsaid fixed contact plates to one terminal of. said source and comprising in part a path from the remaining terminal of said source to a set of switching elements; said circuit being open, said second path is extended to one of said brushes and said circuit being closed through said one of said brushes said path is extended through said switching elements to the second of said brushes.

3. In an automatic telephone system, a double searching brush; a series of fixed plates searched over; and a relay charged by current through the first brush of said double brush and operating when so charged to isolate said first brush and to continue its energization through the second brush of said double brush.

l. In an automatic telephone system, a series of fixed contacts; a pair of brushes movable over said contacts; means for moving said brushes continuously; means for stopping said brushes when a controlling circuit is closed through the first of said brushes and means for transferring said controlling circuit to the second of said brushes.

5. In an automatic telephone system, a series of fixed contacts; a pair of brushes movable over said contacts; mechanical means for moving said brushes continuously; mechanical means for stopping said brushes when charged by current received through one of said brushes; and means for transferring the control of said stopping means to the second of said brushes, said last means being operated as a detail of the act of stopping the brushes.

6. In an automatic telephone system, a series of fixed contacts; a pair of brushes movable over said contacts; mechanical means for moving said brushes continuously a clutch for stopping said brushes; and an electrical switch controlled by said clutch for isolating the leading brush of said pair.

7. In an automatic telephone system, series of fixed contacts in sets; two detector brushes leading and lagging respectively; an operating brush in angular alinemcnt with said lagging brush to engage another contact of any set oi fixed contact points simultaneously with said lagging brush; detector circuit through said leading brush; means whereby said detector circuit acts to stop said brushes and means for isolating said leading brush and for maintaining said brushes stopped.

S. In an automatic telephone system, a set of fixed contact plates; a set of brushes adapted to move over said plates; a leading brush accompanying said set of brushes; means for stopping said set of brushes upon a selected set of contact plates, said means in stopping said brushes operating to permit said leading brush to overshoot the contact plates of the selected set; and further means associated with said stopping means for isolating said leading brush.

9. In an automatic telephone system, fixed contact plates in sets; a set of brushes mow able over said contact plates; another brush associated with said set and in a leading position with reference to said set; means "for stopping said. set of brushes in engagement with a selected set of contact plates; a circuit for actuating said stopping means initially, said circuit comprising in part said leading brush; and means for continuing the energizing of said stopping means.

1.0. In an automatic telephone s fixed contact plates in sets; a set of brusoes movable over said fixed contact plates; a detector brush associated with said set of brushes; a circuit comprising in part said detector brush and one of said contact plates; a clutch for stopping all of said brushes; and an electric switch for opening the circuit of said detector brush.

11. In an automatictelephone system, fixed contact plates in sets; a set of brushes movable over said fixed contact plates; a detector brush associated With said set of brushes; a circuit including said detector brush; a clutch for stopping said brushes; and an electric switch controlled by said clutch for opening the circuit of said detector brush. o

12. In an automatic telephone system, fixed contact plates in sets; a set of brushes; a detector brush; means for moving said brushes continuously; a circuit including said detector brush; a clutch for stopping said brushes; and means for opening the circuit of said detector brush.

18. In an automatic telephone system, fixed contact plates in sets; a set of brushes; a detector brush; means for moving said brushes continuously; a circuit including said detector brush; a clutch for stopping said brushes and means for opening the circuit of said detector brush, said circuit opening means operated by said clutch.

14.111 an automatic telephone system, fixed contact plates in sets; a set of brushes; a detector brush; means for moving said brushes continuously; a circuit including said detector brush; a clutch for stopping said brushes; means for opening the circuit of said detector brush, said circuit opening means holding said circuit open While said brushes are motionless.

15. In an automatic telephone system, an arc of fixed contact plates subtending equal angles; a brush; means for moving said brush continuously over said contact plates; means for stopping said brush and permitting in said brush a limited angle of movement between the position of the brush when the stopping means is energized initially and the position of the brush when stopped, said permitted brush angle being greater than the angle subtended by a fixed contact plate.

16. In an automatic telephone system, a fixed contact plate; a brush; a continuously moving shaft driving said brush at a uni form speed over said plate; a clutch mechanism for stopping said brush, the time interval for stopping the brush being greater than he time interval of engagement of the brush with said contact plate.

17. In an automatic telephone system, a plurality of fixed contact plates; a multiple searching brush; means for moving the brush over the plates; circuits and mechanism associated with the brush for stopping the brush, the angle permitted for stopping the said brush being greater than the angle subtended by one of the fixed contact plates.

18. In an automatic telephone system, a series of fixed contact plates; a detecting brush; means for moving said brush with uniform motion over said plates; a clutch for stopping said brush; a circuit controlling the initiation of the actuation of said clutch and comprising in part said detecting brush; and a further circuit continuing the actuation of said clutch and independent of said detecting brush.

19. In an automatic telephone system, a series of fixed contact plates; a detecting brush; a following brush; means for moving said brushes with uniform motion over said plates; a clutch for stopping said brushes; a circuit controlling the initiation of the actuation of said clutch and comprising in part said detecting brush; and a further circuit for continuing the actuation of said clutch and independent of said detecting brush.

20. In an automatic telephone system, a series of fixed contact plates; a searching 90 brush; other brushes; means for moving the brushes continuously over the plates; means for stopping the brushes; a circuit for actuating said stopping means and including said searching brush and detected contact plate; and further operating circuits and including a brush displaced angular-1y to follow the searching brush and operating to continue the actuation of the stopping means independently of the searching brush.

21. In an automatic telephone system, a series of contact plates, a multiple searching brush having leading and lagging brushes as parts thereof; means for moving said brushes continuously until a detected con- 105 tact plate is engaged by the leading member and stopping means for said brushes actuated initially by the leading member and subsequently by the lagging member of said multiple brush.

22. In an automatic telephone system, a series of contact plates; a multiple searching brush having leading and lagging brushes as parts thereof; means for moving said brushes continuously until a detected con- 115 tact plate is engaged by the leading member; stopping means for said brushes actuated initially by the leading member and subsequently by the lagging member of said multiple brush; and means associated with 120 said stopping means for opening the circuit of said leading brush member.

23. In an automatic telephone system, a series of contact plates; a multiple searching brush having leading and lagging brushes 125 as parts thereof, means for moving said brushes continuously until a detected contact plate is engaged by the leading member; stopping means for said brushes actuated initially by the leading member and subse- 180 quently by the lagging member of the said and Province of Ontario, in the presence of multiple brush; and means associated with two Witnesses.

said brush-stoppin means for isolating said leading member of said multiple brush from DAVID HULFISH' said brush-stopping means When said brush- Vitnesses: stopping means is fully actuated. WM. J. HERDMAN, Signed by me at Toronto, county of York, H. M. CI-IRISTMAN.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. G. 

